Cationic polymers are macromolecules bearing positively charged groups, usually quaternary ammonium or protonated amine functions, either along the backbone or on side chains [1]. The charge density, set by the fraction of ionisable monomers and by the degree of protonation at a given pH, governs how the chain binds to anionic surfaces of nucleic acids or cell membranes [2]. Because the charge is distributed over many repeat units, the polymer binds multivalently and condenses counter-charged macromolecules into complexes, an effect not available to a monovalent cation [3]. They differ from anionic and neutral polymers in that electrostatic attraction, rather than hydrogen bonding or hydrophobic association, dominates their interaction with dissolved polyelectrolytes [1].
- quaternary ammonium polymer
- charge density
- polyelectrolyte complex
- protonated amine
- multivalent binding
References
- Crini, G.; Kinetic and equilibrium studies on the removal of cationic dyes from aqueous solution by adsorption onto a cyclodextrin polymer. Dyes and Pigments 2008, 77, 415-426, 10.1016/j.dyepig.2007.07.001.
- Tang, M.; Szoka, F.; The influence of polymer structure on the interactions of cationic polymers with DNA and morphology of the resulting complexes. Gene Therapy 1997, 4, 823-832, 10.1038/sj.gt.3300454.
- De Smedt, S.C.; Demeester, J.; Hennink, W.E.; Cationic Polymer Based Gene Delivery Systems. Pharmaceutical Research 2000, 17, 113-126, 10.1023/a:1007548826495.